System for automatically aligning and/or moving in a parallel movement path a guide seating structure adapted for guiding the movement of a tool mounted thereon

ABSTRACT

The object of the invention is a system for automatically setting the angles of the guide seating structure of a rock drilling machine or the rammer of a pile driver, or a similar tool arranged for a reciprocating movement on said structure carried by a movable support and for moving the structure parallel to itself so that the angle of the structure is maintained. The structure is pivotally mounted in two substantially vertical orthogonal planes and is connected to the movable support by a movable intermediate arm provided with drive means such as jacks for pivoting movements of the structure in said two planes. Transducers are mechanically coupled to the drive means to transmit electrical signals representing angles to a comparator in response to the attitude of the guide seating structure, the intermediate arm and the seating structure to adjust the seating structure to a specific bearing and a specific angle, in said two planes, in relation to the vertical, the bearing and the specific angle being automatically maintained when said movable support carrying the guide seating structure is moved to another place even on a terrain of varying slope so that a further hole may be drilled or a further pile may be driven exactly parallel to a preceding one.

United States Patent Dahlstrom et a1.

1451 July 29,1975

[54] SYSTEM FOR AUTOMATICALLY 3,6l2,190 10/1971 Wills 173/20 A 3,625,483l2/l971 SIOIICI' 280/6 H PARALLEL MOVEMENT PATH A GUIDE SEATINGSTRUCTURE ADAPTED FOR Prmzary bxammerErnest Purser GUIDING THE MOVEMENTOF A TOOL Attorney, Agent, or FzrmP1erce, Scheffler & Parker MOUNTEDTHEREON [Q7 ABSTRACT [75] Inventors: Carl Lennart Dahlstrom, Savedalen;1 Tord Richard William Pomon, The ob ect of the 1nvent1on 1s a systemfor automat1- MoIndaI both of Sweden cally setting the angles of theguide seating structure I of a rock dr1lI1ng machme or the rammer of ap1le Asslgneei AB Skanska Cememglutel'let driver, or a similar toolarranged for a reciprocating Sweden movement on said structure carriedby a movable sup- I22I Filed: sept 10, 1974 port and for moving thestructure parallel to itself so that the angle of the structure ismamtamed. The

[ PP 504,702 structure is pivotally mounted in two substantially ver-Related Application Data tiIclal orthogorIgal planes and is conrzIectedto the nadovII [63] Continuation of Ser. No. 206,480, Dec. 9, 1971, e Fy amova 6 f prov e abandoned with dl'lVC means such as acks for p1vot1ngmovements of the structure in sa1d two planes. Transducers I30] ForeignAppncafion Priority Data are mechanlcal ly coupled to the dr1ve means totrans- I68I H mlt electrlcal slgnals representmg angles to a compar Dec.11,1970 Sweden SI 7 ate], in response to the attitude of the guideSeating Apr. 21, 1971 Sweden 51 1 structure the Intermediate arm and theseating Strum ture to adjust the seating structure to a specific bear-[52] U.S. C1. 173/2, 33/;ZgI217238/3/2g Ing and a Specific angIe, InSaid two pIaneS In reIatIon SI I CI E21 11/02 to the vertical, thebearing and the specific angle f 248/2 being automatically maintainedwhen said movable 1 0 care support carrying the guide seating structureis moved to another place even on a terrain of varying slope so [56]References Clted that a further hole may be drilled or a further pilemay UNITED STATES PATENTS be driven exactly parallel to a preceding one.2,101,837 12/1937 Blanchett 280/6 H 3,481,409 12/1969 Westerlund 173/4321 D'awmg F'gures Wn/TrTuGficuTfiuRm G I l5 I LFROM oonmmmnfls E fiB 115111 +5 PULSE nvnlmu I 213312 muvmc 501.511. PISCIOII I STAGE VALVE FEEDl .R\\ BEAMIL I x.1' FHY I I l PENEL REENEEE l I I g 11%; I0 I L. l l I"film n 5LPE l 1 l I nf l c li t on I 20R fsgafa SELEUOR 011 FROM lCOURSE f I l I I COMPARATOR l i' u n LHLT J I INDICATOR I III I I I I II/l R0"- 1 o D O 1.0w AMPL. PULSE 4 vuruul it??? lac-mat I P731 211 IIEE' ts??- 3116'? 1215; 3, 9 l I W.SI GHT UFLING -(-l) I I SLO-PE LAT R11L} I zlfil'l'lAcTloN I SELECT, ,7 I K cos(%*t I l K241 LOW l I ma 1 IOPERATING CIRCUIT TILTING SHEET PATENTED JUL2 9 I975 SHEET PATENTED JUL2 9 I975 6 0: .z i ww 10 fl 1 5 1 w we W1. "Ev m a 14 oz; 9: v. Q G m um NOE SHEET PATENTEI] JUL 2 9 I975 SHEET PATENTEU JUL29|975PATENTEUJULZSIHIS 3,896,885

sum e FIG.7

mcuumou OF FEED BEAM BEARING PATENTEBJULZQIHYS 3,896,885

SHEET 7 FIG.8

INCLINATION OF FEED BEAM )5 SYSTEM FOR AUTOMATICALLY ALIGNING AND/ORMOVING IN A PARALLEL MOVEMENT PATH A GUIDE SEATING STRUCTURE ADAPTED FORGUIDING THE MOVEMENT OF A TOOL MOUNTED TI-IEREON This is a continuationof application Ser. No. 206,480 filed Dec. 9, 1971 and now abandoned.

The present invention relates to a system for automatically aligningand/or moving in a parallel movement path a guide seating structureadapted for guiding the movement of a tool mounted thereon, the guideseating structure being pivotally mounted in two planes located atangles relative to each other on elements which are arranged to supportthe seating structure and connected between the structure and a movablesupport unit and provided with drive means for effecting the pivotingmovements of the guide seating structure in the aforementioned planes.

Guide seating structures of the type envisaged are used, inter alia, inthe form of feed beams or runners for rock drilling machines which arearranged for reciprocating movement along the beams, although suchseating structures may also be used in other connections, for example inthe form of guide structures along which working tools such as dropweights are arranged to move.

When using such guide seating structures it is important that they canbe aligned to point in the desired direction as simply and as accuratelyas possible and that they can be moved in a parallel path of movementfrom one working site to another, so that the tools arranged thereonretain the same position in relation to the vertical and to thehorizontal. This is the case, for example, with guide seating structureshaving the form of runner beams for rock drilling machines, in whichcases it is often desired to change both the angle at which the beamsare inclined to the horizontal and the direction in which the seatingstructures are pointed, i.e. their directional bearing, a task which hashitherto been relatively time consuming and which requires a high degreeof precision in order to obtain sufficient accuracy, and wherein withtunnelling and bench blasting it is of great importance that adjacentlysituated drill holes extend parallel to one another. For these purposes,the guide seating structures of rock drilling machines are arranged forpivotal movement in the aforementioned two planes, the guide seatingstructures being guided manually and moved by means of their respectivedrive means in a manner such as to enable them to be brought intodesired positions and when moved from one working site to another theseating structures can be adjusted so that parallellism is obtainedbetween the settings of the seating structures at the different workingsites. This, however, is a method which must be carried out with greataccuracy and which is consequently highly time consuming particularly ifa sufficiently accurate degree of parallellism is to be obtained whenbench blasting, with which it is often difficult in practise to checkthe bearing of the guide seating structures.

Although certain suggestions have been made for varying degrees ofmechanized alignment and parallel movement of the feed beams of rockdrilling machines, none of these proposals have paid sufficientattention to the influence of the widely varying contours of the surfaceto be drilled in bench blasting operations, or to.

the bearing of the beams, the word bearing being used here to indicatethe direction in which the beams point in the horizontal plane.

The object of the present-invention is to eliminate the disadvantagesassociated with the aforementioned proposals and to provide a system ofthe type described in the introduction which in addition to the factthat it can be mounted directly to the elements forming the connectingmeans between the support unit and the seating structures, irrespectiveof the design of the elements, also provides the desired setting of theseating structure both subsequent to a change in slope and to a changein direction of the supporting unit, without it being necessary for theoperator to make a new setting on the system. In other words, the systemaccording to the invention shall be capable of providing a setting andparallel movement of the guide seating structures or the feed beamswhich is substantially independent of the machineconstruction, thecontours of the ground and the bearing.

Practical tests carried out on embodiments of a system according to theinvention show that the aforementioned objects are satisfactorilyachieved and that by means of said system it is possible to align andadjust automatically the guide seating structure with respect to itsbearing and inclination to the vertical and to move the guide seatingstructures automatically in a parallel pattern of movement. The systemof the present invention thus affords a solution to a problem which wasdifficultly resolved and time consuming and enables the desiredinclination and bearing of the seating structures to be obtained easilyand precisely, simply by making certain settings on an instrument panel.

The system of the present invention is mainly characterized in thatinterconnected transducers and comparison units are coupled to the drivemeans of the guide seating structure and are arranged to transmitsignals in response to the attitude of the supporting unit, the meansconnected between the guide seating structure and the supporting unitand/or the seating structure to adjust the seating structure to aspecific bearing and a specific angle in relation to the vertical.

The invention will now be described with reference to the accompanyingdrawings, further features of the invention being disclosed inconnection therewith.

In the drawings, FIG. 1 illustrates diagrammatically a side view of amobile rock drilling unit provided with guide seating structures in theform of feed beams arranged to guide thereon tools in the form of rockdrilling machines arranged for reciprocal movement along the beams,

FIGS. 2 and 3 are simplified, diagrammatic views of the rock drillingunit seen in top plan view and from the rear,

FIG. 4 is a block diagram of an embodiment of the system according tothe invention responsible for adjusting the positions of the feed beamsand moving the same in a parallel pattern of movement,

FIG. 5 is a view corresponding to the view of FIG. 2 and illustrates arock drilling unit provided with a system according to the inventionintended for adjusting the positions of the feed beams and moving themin a parallel pattern of movement,

FIG. 6 is a block diagram of the embodiment illustrated in FIG. 5, and

FIGS. 7 and 8 each show an example of calculating means for controllingthe feed beams of a drilling unit according to FIG. 5.

The rock drilling machine illustrated in FIGS. l-3 and FIG. is of purelyconventional construction. The machine is supported on a body member orsupport unit 2 mounted on tracks I, which enable the unit to be moved onthe working site. In the illustrated embodiment, the body member 2pivotally supports two folding jibs 3 which can be raised and loweredrelative to the body member. The folding jibs are attached at one end tothe body member and each of the jibs carries at its free end a feed beam4. The feed beams comprise guide seating structures for guiding a rockdrill unit 5 arranged thereon, each of the drill units being arrangedfor reciprocating movement along its associated beam thereby to movea-drill 6 to the desired working position.

The two feed beams or seating structures 4 are mounted on the jibs 3 ina manner which enables them to be pivoted in two planes at right anglesto each other so that the seating structures can be tilted and turnedrelative to a vertical line through their pivoting axes. The tilting andturning movements effected by the seating structures in planesperpendicular to each other are illustrated in FIGS. 1 and 3, in whichthe tilting angles and the turning angles are shown by the reference 'yand y respectively, these angles thus lying in their respective one ofthe two planes. The pivoting movements of the seating structures 4 inthe aforementioned planes are effected by means of drive units in theform of hydraulic mechanisms 7 and 8. The hydraulic mechanism 7 isresponsible for movement of the seating structure in the tilting plane,while the hydraulic mechanism 8 is responisble for movement of theseating structure in the turning plane. The hydraulic mechanisms 7,8cooperate with hydraulic mechanisms (not shown) for manoevring thefolding jibs 3 by means of oil pressure obtained from one or more pumpsmounted on the body member 2.

In as much as a system according to the invention is intended both foradjusting the position of a seating structure for guiding a toolarranged thereon and for moving the seating structure in parallelmovement patterns and since the illustrated embodiment is provided withtwo' such seating structures, namely the feed beams 4 supporting therock drilling units 5, which beams can both be adjusted and moved inparallel movement paths individually between their different operationpositions, two co-acting devices must be arranged in the two illustratedembodiments. In accordance with the invention, the co-acting devicescomprise interconnected transducer and comparison units coupled to thedrive means 7,8 of each seating structure or feed beam 4, the transducerand comparison units being arranged to transmit signals forautomatically adjusting each of the seating structures to a specificbearing and to a specific angle relative to the vertical in response tothe attitude of the body member 2, the means in the form of folding jibs3 coupled between the body member and the seating structures and/or theindividual attitudes of the seating structures or feed beams.

In view of the fact that a system according to the invention in additionto determining the attitude of the tion so as to facilitateunderstanding of the invention. With respect to the first embodiment,FIG. 2 also illustrates how a signting device co-acting with a directionor course indicator 9 mounted on the body member 2 is adjusted to thedesired course or bearing for the feed beams 4. In respect of the secondembodiment, FIG. 5 illustrates in a corresponding manner how thesighting device co-acting with course indicators mounted on the bodymember 2 and corresponding to at least one of the course indicators 12mounted on the feed means is adjusted to the desired course or bearingfor the feed beams 4.

For the sake of simplification, the block diagram illustrateed in FIG. 4for the rock drilling unit illustrated in FIGS. I3 and relating to thefirst embodiment of the system according to the invention, in additionto the circuits for the bearing of the body member 2, only shows theoperating circuits for effecting movements in the turning and tiltingplanes for one of the two feed beams 4 associated with the unit inquestion.

As will be evident from FIG. 4, in principle the operation of the systemis similar to that of a fire control system for naval artillery. Thecourse indicator 9, which is the all important unit for determining thebearing of the feed beams, may be constructed in different ways and, forexample, may comprise a compass provided with a compass indicatorhousing rotatably mounted in an operating box and provided with a coursefollower capable of being actuated from without by means of gears via atransmission having a gear ratio of l:(l The course follower isconnected through the transmission with the knob of a resolver 10 in amanner such that rotation of the resolver knob in a clockwise directionresults in anitclockwise rotation of the course follower and vice versa.As will be seen from the reference disclosed in FIG. 2, the referencesfor both the resolver knob and the course follower in the longitudinaldirection of the drill unit is straight forwards. To facilitate workconnected with adjusting the bearing of the feed beams which, interalia, may be given in relation to sighting marks on the ground, theindicator housing of the course indicator 9 is suitably provided with anattachment means for a sighting telescope or the like. The sightingtelescope should be connected to the indicator housing by means of theattachment means such as to be stationary with respect to the housingbut arranged for rotation with the housing in the operating box and havea reference position pointing straight forwards in the longitudinaldirection of the drilling unit, i.e. that a special designation, e.g. N,on the scale of the indicator housing points straight forwards in thelongitudinal direction of the unit.

With respect to the angles a, B and III, illustrated in FIG. 2, atransmitter portion of the course indicator 9 transmits signal voltagesto the resolver 10 which constitute a measurement of the angle (B-l-tb).When the course indicator needle lies on the designation N on the scaleof the indicator housing the angle (Bi'lil) is 0, while the bearing ofthe drilling unit is also 0.

To obtain behind the resolver 10 a signal which is representative of ameasurement on only the angle 4:, which indicates the desired angulardeviation in the feed beam bearing relative to the longitudinaldirection of the unit pointing straight forwards, it is necessary withthe system of the embodiment illustrated in FIG. 4 to direct thesighting telescope, and as a result thereof also the indicator housingfor the course indicator 9, to

the desired bearing and locked therein'. -Ther'eafter,- the knob on theresolver is'turne'd so that the course follower of the courseindicatoris movedin a direction coinciding with the direction of the indicatorneedle,

whereupon the resolver knob is locked. Subsequent to thesemeasures-being taken, the settingnofthe system provides reference.values for-all future'changes in direction of the drilling unitprovided that the adjusted desired bearing is to be maintained, i.e. thesignal behind the resolver 10 is always a measurement on the angle t1:irrespective of how the drilling unit is turned on its tracks 1. r

Setting of the feed beam bearing by means of a system according to FIG.4 can be explained simplest by assuming that the sight with theindicator of the course indicator 9 and the course follower andtherewith also the knob of the resolver 10 all point straight forwardsin the longitudinal direction of the drilling unit. The needle of thecourse indicator will then take a position corresponding to the angle(B+il1) in relation to the longitudinal direction of the unit andtherewith also in relation to the course follower. If the sight is nowturned together with the course indicator to the angle (-111) so thatthe sight points in the desired direction for the feed beams 4, thecourse indicator needle will still show the angle 5w) relative to thescale on the course indicator, but will itself take the angle B relativeto the course follower and the straight forward direction in thelongitudinal direction of the unitQIf the knob of the resolver 10 is nowset so that the direction in which the course follower extends coincideswith the direction of the indicator needle, i.e. with the angle (-8),while the course follower turns anti-clockwise when the resolver knob isturned clockwise, the resolver subtracts the angle ,8 from the courseindicator reading, whereby the output signal from the resolver 10 is ameasurement of the angle (11 unit a new setting is made, irrespective ofhow the drilling unit is turned.

If the sight is not required for use in adjusting the feed beams to thedesired bearing, but that the number of degrees through which the feedbeams must be moved in order to reach the bearing are known, therequisite number of degrees can instead be set directly on the knob ofthe resolver 10, since the course follower connected thereto is alsorotated to the desired position on the course indicator scale. Thus, inthis instance use of the sight is obviated, the sight being mainlyintended to obtain bearing settings for which only reference objects inthe surrounding territory are found.

With the system shown in the block diagram of FIG. 4, attached to thepivot by which a folding jib 3 is connected to the body member 2 of thedrilling unit is the resolver 11 which senses the swinging movements ofthe jib in the plane of the ground and relative to the body member. Theresolver 11 is not illustrated in FIGS. l3, but is shown graphically inFIG. 4.

Moreover, a, is added'in theresolver 11 to the signal arriving from theresolver l0and the sine and cosine of the sum is formed, whereby therelations K sine (a,, +xl1) and .K cosine (04,, +41) are obtained asoutput signals to;the two operating-circuit 15 and 16 for a feed beam4,.the signals comprising references for rotation and tilting,respectively, ofrthe feed beam setting.

Incorporated in the operating circuits 15 and 16 is an inclinationselector 17, whichmay be-either of the socalled continuous typeorso-called indexing type and is intended for adjusting the slope of thefeed beam relative to the vertical. The signals arriving from theresolver 11 and combined subsequent to being demodulated and filtered inthe two operating circuits 15 and 16 with the signal arriving from theinclination selector 17, which is common for the two circuits, and isthen transmitted in the form of a set-point signal for the slope of thefeed beam in its plane of rotation and a setpoint signal for the slopeof the beam in its tilting plane to each of the comparison means 18 andI9 incorporated in the two operating circuits. A control signal is thentransmitted from the comparison means 18 in the operating circuit 15 formovement of the feed beam 4 in the rotation plane, which actuates asolenoid valve of the hydraulic mechanism 8, the hydraulic mechanismmoving the feed beam in its plane of rotation until the desired positionis obtained. Arrival at the desired position is decided by a signaltransmitted from an appropriate pendulum transducer 20 mounted on thebeam in its plane of rotation and arranged to detect the angularposition thereof, which signal, subsequent to being suitably processed,is returned to the comparison unit 18.

As will be evident from the aforegoing, the transducer means provided inthe system according to the invention comprises, inter alia, means whichsense angles in the plane of the ground.

In the described embodiment, the transducer means comprise the meansco-acting with the course indicator 9 mounted on the body member 2 andthus primarily the resolver l0 and the resolver 11 which is mounted onthe attachment pivots of the folding jibs 3 to the body member 2 andsenses the-mutual angle between respective folding jibs and the bodymember. Furthermore, the transducer means comprises means which senseangles in the vertical plane, which means in the described embodimentcomprise two vertical sensing instruments or pendulum transducers 20 and21, which are mounted on the feed beam or on the seating structure 4, orwhich in principle may be mounted on the rock drilling machine 5 intheir respective ones of the two vertical planes in which the seatingstructure or beam 4 is capable of moving.

The acutal setting of the angle of the feed beam or seating structure 4in relation to the vertical and the bearing of the feed beam or theseating structure is effected, as previously disclosed, by means of theinclination selector 17 with respect to the angle and a selector means,for example in the form of a resolver 10, with respect to the bearing,coacting with the instrument disclosing the direction, in the presentcase the course indicator 9.

The embodiment of the system according to the invention illustrated inFIG. 4 can be applied in such instances when the body member 2 is in asubstantially horizontal position and will adjust the position of thefeed beams 4 with sufficient accuracy to satisfy the majority ofrequirements in practice when the slope of the ground varies to amoderate extent. The most important advantage with this embodiment isthat one single course indicator is able to serve several seatingstructures or feed beams 4 and that in certain case it has been foundmore suitable to position the course indicator on the body member. Onthe other hand, the embodiment disclosed in the block diagram of FIGS. 6and 5 can be used when no requirements are placed on a substantialhorizontal attitude of the body member, i.e. irrespective of variationsin ground slope.

With the embodiment of FIGS. and 6, a course indicator 12 is used foreach separate feed beam 4 so that information concerning the twovertical planes in which respective feed beams are turned and tipped canbe obtained directly from the course indicators (see FIG. 5). This isachieved, for example, by the fact that the course indicator 12 (FIGS. 5and 6) is mounted either on the actual feed beam 4 or on an extensionthereof, where it is oriented so that it discloses directly thedirection of the vertical plane in which the beam or the seatingstructure 4 is tilted. The course indicator 12 may also be mounted onthe actual tool, i.e. in the illustrated embodiment on the drillingmachine 5, since the tool is unable to rotate around an axis in thelongitudinal direction of the seating structure or the feed beam 4.

When initially aligning the feed beams on marks in the surroundingcountryside while using the second embodiment of the system according tothe invention, the body member 2 shall be positioned horizontally and atleast one folding jib 3 should be directed straight forwards in thelongitudinal direction of the rock drilling unit, see FIg. 5. Theprocedure when adjusting the position of the different members is thensimilar to that undertaken with the first embodiment of the systemaccording to the invention. It should be mentioned, however, that theresolver knob is common to the two feed beams 4 and is thereforeconnected to the resolver l0 cooperating with each of the beams. In thisway, the angle ,8 can be subtracted simultaneously for the two feedbeams, which means that the outgoing signal from each of the tworesolvers 10 is a direct measurement of l om and lll respectively. Aswill be seen from FIG. 5, (1J0 discloses the angular deviation betweenthe vertical planes in which the beams are tipped and the desired coursedirection or bearing. I

When the direction in which the feed beams are directed is adjustedaccording to information obtained from the course indicator, theprocedure is the same as that taken with the previously describedembodiment of the system according to the invention, i.e. therequirement of a horizontal position and forward direction of a foldingjib is obviated.

The block diagram illustrated in FIG. 6 also discloses only one of thefeed beams 4 embodied in the apparatus. The system illustrated in FIG. 6also operates in a manner approximately similar to a fire control systemfor naval artillery.

The course indicators 12 of the illustrated embodiments are combinedtransducer devices arranged to transmit signal indicative of thedirection in which the feed beams are pointed and their indication andare immovably connected with their respective feed beam 4 or other typeof seating structure or the working tool and will always move togetherwith the tool. Thus, with the exemplary embodiment it is not necessaryto provide universal joints or other forms of pendulating suspensionmeans or corresponding stabilized platforms. The coordinate system ofthe aforementioned transducers is thus established in relation to theseating structure and movable relative to the vertical and to thegravitational and magnetic field of the earth, and consequently it isnecessary to make corresponding calculations for obtaining signals foradjusting the seating structure to a determined bearing and to adetermined angle relative to the vertical.

The following advantages are gained by mounting the transducersstationarily with respect to the seating structures 4:

a. attachment of the indicators to the seating structures and theattachment members necessary therefor can be effected with comparativecase;

b. the transducers need not be constructed to contain movable componentsor to cooperate with such movable components as inclination indicatingpendulum transducers or the like,

0. Since the transducers are not fitted with movable components andsince no mechanical damping means for pendulating systems and universaljoint suspensions etc, are required, the transducers will operate morerapidly.

d. The risk of damage to the transducers and components cooperatingtherewith is less which is of great importance in the case of rockdrilling units and similar machines operating under difficult workingconditions.

Although a system employing course indicators having a magnetic compassand universal joint suspension together with pendulum transducersnecessary therewith and optionally damping means and the like is atpresent less expensive than a system employing transducer means which bymeans of immovable elements determine the components of the earthsmagnetic field, even when taking into account the costs involved for thenecessary automatic calculating means, the aforementioned advantagesafforded by the latter system more than offset the extra costs involved.It should also be mentioned that a transducer which has no movablecomponents and which is mounted directly onto the seating structures 4is subjected to much harder vibration than a transducer mounted on thebody member and possibly resiliently suspended by universal joint means,but modern devices for measuring the components of the earths magneticfield (in in the present instance it is only the angles of thesecomponents or their relative magnitude in relation to each other whichneed be determined) are very small and insensitive and can be readilymounted in position, optionally on shock absorbers or the like, and areof very inexpensive construction. Examples of such modern fieldcomponent measuring devices are semi-conducting devices providing withso-called magnistors, magnetodiodes or fluxgate magnetometers.Hall-transducers and so-called field plates are less suitable for use atthe present time.

FIGS. 7 and 8 each show an embodiment of a calculating means whichtransmits signals for controlling the desired tilting and rotation ofthe feed beams or seating structures 4, the tilting and rotation of theseating structure being effected by means of the hydraulic units 7 and8.

To enable the purpose and mode of operation of the devices illustratedin FIGS. 7 and 8 to be understood, a description will be given of thecalculations which must be carried out by the devices. For the sake ofsimplicity, the description will be given solely with reference to thecase when the rock drilling unit is provided with only one feed beam 4having attached thereto a combined inclination and course indicator 12.In the case of two or more feed beams which can be rotated and tiltedindependently of each other, one indicating means and one calculatingdevice must be provided for each beam.

The coordinate system of the combined indicator 12 is a right-angleright-hand system and is independent of the vertical or the coordinatesystem of the magnetic and gravitational field, the coordinate axes ofthe indicator being x, y and z. The vertical and the coordinate axis 2of the indicator will only coincide when the feed beam 4 is vertically,i.e. when the axis 2 extends vertically downwardly, while x coincideswith the straight forward direction of the interconnected member 3 and yis directed horizontally to the right in the transverse directionperpendicular to both the vertical and to the axis x.

The horizontal projection of the coordinate axis x forms the angle ill,with the desired bearing ,3. The coordinate axis 2 forms the angle 7with the vertical. The desired inclination of the feed beam is 'y Theprevailing tilt and rotation angles of the seating structure 4 (thecontrol point values) are 7, and 7 The horizontal and verticalcomponents of the earths magnetic field are 8,, and B respectively. Theearth field components measured by the transducer in the transducercoordinate system 2:, y, z is B,, B and 8,, respectively. If theinclination angle of the earths magnetic field is designated j, theinclination I tg j B /B The signal representing the difference betweenthe control-point value and the set-point value of the tilt isdesignated S, and the corresponding signal for rotation is designatedS,,, these two signals being so-called error signals which control thetipping and rotating hydraulic unit 7 and 8 by means of servo controlmeans.

The following relationships are applicable for controlling the seatingstructure by means of the last mentioned signals:

S,. siny sim/ coslll (2) It is now assumed that there is used atransducer of known design which generates electric signals, each ofwhich represent one of the three magnetic components B 8,, and B,suitably so that the signals are proportional to these components.Electrical signals are produced by the aforementioned signals in, forexample, matching amplifiers (not shown) representing B /B B,,/B, and B/B representively. The ratio I= B,,/B,,, i.e. the value I of theinclination, which is equal to the tangent of the inclination angle, canalso be formed in a similar manner. It should be observed that thevertical and horizontal components 8,, and 8,, of the earths magneticfield can normally be considered constant, and hence it is onlynecessary to set these values once, although possibilities of adjustingthe same should be found; setting of the values being effected byadjusting the amplification factor of the aforementioned matchingamplifiers in a corresponding way. Thus, the two earths magneticcomponents need not be constantly measured by a special transducer orthe like.

The calculating means illustrated in FIGS. 7 and 8 make calculations onthe basis of the following:

B, 8,, cos (3 Sin 7+ B cos y cos y= cos 'yv cos yr (6) The variable y inthe equations (3)-(5) is then eliminated by means of the equation (6),whereafter the three values w, W and th are calculated from these threeequations.

The following relationships are obtained when inserting the inclinationI tgj B /B B ,./B, cos (,8+lll cosyt 1 sin 7! (3a) In a manner similarto that when inserting the two, normally constant values B and 8,, inamplifiers which directly or by means of subsequent stages generatesignals corresponding to B /B B lb, and B /B the ratio I B /B, candetermine the amplification factor in amplifiers referred to more below.It should be mentioned here that the values I, B, and are natural valuesand, as is well known, may vary slowly with time and may be slightlydifferent in different geographical areas. Information on such values ispublished annually by relevant authorities. In the following descriptionit is assumed that the exemplary devices are provided with adjustingmeans to permit corrections to be made to the aforementioned values.

In connection with the following description it should be held in mindwhat has previously been said with respect to the three natural valuesand, furthermore, that cos y! cos yu= cos y and that with respect to theinclination angle 7 the approximation can be made that the tangentthereof is approximately equal to its sine, since it is oftenunnecessary to calculate on large degrees of slope and to assume agreater degree of accuracy than this approximation affords, in order tosimplify the calculating means.

The devices illustrated in FIGS. 7 and 8 are the same with respect tothe connecting means and mechanical, normally manually operatedadjustment means embodied therein although, as previously mentioned, theadjustment means for the values B 8,, and I B /B, have not been shown.

Each device is provided with a suitably manually adjustment 31 for thedesired angle of inclination y and a similar means 32 for the desiredbearing angle B, the adjustment means being in the form, for example, ofwheels or small levers for rotating a resolver (R) which formstrigonometrical functions from these an gles. Furthermore, each deviceis provided with three inputs X, Y and Z adapted for connection to thetransducer, which transmits to said inputs the measured relative valuesB /B B B, and B /B respectively, obtained from the transducer, saidvalues being the control-point values and will be compared with thesetpoint values in the calculating device.

In FIGS. 7 and 8, the three concentric double rings marked X, Y and Zindicate the inputs, as aforementioned. The devices are also providedwith outputs A and B, the output A sending the error signal to the tiltThe single line between the units indicates the electrical connections,while mechanical adjustment shafts are indicated by a double line and acurved arrow.

The output identified by the reference numeral 1 is connected to anelectric signal, e.g. a fixed voltage, the signal representing the value1 l forming in a subtraction stage, SUB, the value lcos y by applying tothe subtract input of the circuit a signal corresponding to cos y.

In other respects the devices include: resolvers R, servomotors M forthe resolvers, comparators in the form of arithmetical stages such assubtraction, addition and multiplication stages SUB, ADD, DIV and MULT,respectively, and a square root forming stage ROT and operationamplifiers F. The element identified with the reference -I is also anamplifier having adjusted therein an amplification factor in accordancewith the inclination I.

The triangles which identify amplifiers F and I are placed so as todisclose the amplification direction, i.e. the apex of the triangle isthe input and the base is the output. The arrows show the directions ofpropagation of the electrical signals. It should be observed that, inthe absence of special standards, a triangular symbol for an amplifieris often shown inversely drawn. On the majority of the lines in FIGS. 7and 8 have been shown the values representing the signals transmittedover the lines, while the values and directions of the signalstransmitted on the remaining lines can be readily perceived, and hence adetailed description of the two Figures is unnecessary.

In those instances when the two inputs of a multiplication stop MULT areconnected with each other and with a single input line, the stage willnaturally operate as a squaring stage.

In those instances where two or three resolvers R are shown in the formof a double or a treble block, the angle value is transmittedmechanically between the resolvers and can be read directly from thevalues given on the inputs and outputs. For example, there is shown atthe top of FIG. 7 a double block comprising two resolvers R, oneresolver being supplied electrically with trigonometrical values of theinclination angle 7 and mechanically from the lower of the two resolverswith the angle 111 The latter resolver is fed electrically withtrigonometrical values of the set desired bearing angle ,8 andmechanically with the angle 111,, between the horizontal projection ofthe coordinate x and the bearing ,8. The angle 41,, is thus passed fromthe lower of the two resolvers to the upper resolver and, moreover, thelower resolver forms the values sin(B+il1 by means of its input signals.

The calculating device illustrated in FIG. 8 differs from the deviceillustrated in FIG. 7 by the fact that a plurality of multiplicationstages MULT of the device of FIG. 7 are omitted, while a larger numberof resolvers R are used in the device of FIG. 8 than that of FIG. 7. Thedevice illustrated in FIG. 8 employs only one multiplication step MULTdesigned or connected as a squaring stage. When signals representing thesame values are applied to the two inputs of such a stage, the stagewill naturally operate as a squaring stage.

The block diagrams illustrated in FIGS. 7 and 8 primarily relate toanalogue computing devices, although the devices may be constructedtooperate either partially or optionally totally as digitalcomputingdevices in accordance with the illustrated principle; therebyCOMB-H1 0) and providing for a greater degree of accuracy, and mayemploy comparators in the form of arithmetical calculating stages andregisters (storage elements) and also optionally trigonometrical stages(which completely or partially replace conventional resolvers) which arewell known and tested in data technique and relatively inexpensive.

Resolvers exist in a ariety of constructions and need not be describedhere. By way'of example it can be mentioned that the resolver R providedwith the adjusting member 31 and intended to convert B to lg B maysimply comprise a preferably non-linear. e.g. logarithmic,potentiometer, the angular scale for adjustment of the member 31 beingso graded that the potentiometer discloses a voltage proportional to tgBwhen 3 is adjusted in accordance with the scale.

The practical measures taken are restricted to those of manually settingthe desired bearing )8 and inclination 'y whereafter the outputs A and Btransmit error signals according to equation (1) and (2) to theservo-control mechanisms of the tilt and turn hydraulic units, wherebythe feed beam is set to the desired position so that the bearing andinclination remain unchanged irrespective of movements of the workingmachine (the rock drilling unit), i.e. irrespective of the direction inwhich the machine is driven and the slope of the ground.

What we claim is:

1. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like; said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means, formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the vertical and the desired bearing of said structure withrespect to the coordinates of the earth, means for emitting signalsresponsive to the actual bearing and angle of said seating structure tothe vertical when said support unit is moved to a different location,comparator means for comparing the departure of said signals from thepredetermined desired bearing and angle of said seating structure andmeans responsive to the departure of said signals for pivoting means insaid two planes for aligning said at least one seating structure to aposition parallel to the desired bearing and angle.

2. A system according to claim 1 wherein said comparator means includestransducer means having means for sensing the actual bearing in thehorizontal plane and means for sensing the actual angle in relation tothe vertical.

3. A system according to the claim 2 wherein the means for sensing theactual bearing in the horizontal plane includes a course indicatormounted on said support unit and responsive to bearing directions, saidcourse indicator providing a preset desired bearing from which all otherbearings in the horizontal plane may be determined, and furthercomprising a second indicator mounted between said support unit and saidjib means, said second indicator resistering the angle between saidsupport unit and said jib means.

4. A system according to claim 3 wherein the means for predeterminationof the desired angleto the vertical and the desired bearing includes afirst selector means for selecting the desired angle and a secondselector means cooperating with'said course indicator for selecting thedesired bearing.

5. A system according to claim 2 wherein the means for sensing theactual bearing in the horizontal plane includes a course indicatormounted on said at least one seating structure and responsive to bearingdirections.

6. A system according to claim 2 wherein the means for sensing theactual angles in the planes includes at least one pendulum means mountedon said seating structure and being active in the two planes disposed atan angle to each other.

7. A system according to claim 1 wherein the means for emitting signalsresponsive to the actual bearing and angle of said seating structurecomprises a course and inclination transducer mounted for movement withsaid seating structure for producing three magnetic field signals, eachof which represents three coordinate values of a coordinate system whichis immovable in relation to the transducer, and corresponding to threeearth field components of said coordinate system relative to asubstantially fixed component of the earths magnetic field, and saidcomparator means compares the actual values represented by the saidmagnetic field signals with the values for the desired bearing and angleand transmits control signals representing departures between the actualand the desired values to drive said pivoting means for obtaining thedesired bearing and angle of said seating structure.

8. A system according to claim 7 wherein said transducer contains threefield component transducers, each comprising elements which areimmovable with respect to each other and are immovable in relation tothe seating structure and each of which produces com ponent signalswhich are set in relation, to the said fixed components of the earthsmagnetic field so that each of said signals constitutes one of saidthree magnetic field signals.

9. A system according to claim 8 wherein the desired angle and bearingof said seating structure can be manually adjusted and the systemdetermines, with the assistance of said values, the inclination of theearths field, and the three said magnetic field signals, the two controlsignals each representing one of the values:

St gv s B 1 Sv sinyv sinyB cos #1,,

for controlling said pivoting means for the seating structure to obtainthe desired movement in said two planes relative to the vertical, y! andconstituting the actual angle of said seating structure, y/3 being thedesired angle of the seating structure, and 41,, being the angle betweenthe desired bearing ,8 and the horizontal projection of the coordinateaxis in said coordinate system which extends forward in the direction ofsaid jib means.

10. A system according to claim 9 wherein the desired values for theangle 7B,'-the bearing B, the said substantially fixed componentiof'theearths magnetic field and the inclination of the earths magnetic fieldare capable of being adjusted manually, the two last mentioned valuesbeing capableof being preset, and the inclination being adjustable byadjustment of the vertical component of the earth's magnetic field andthe horizontal component to form a ratio of these tw components.

11. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like, said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means, formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said-two planes, means forpredetermination of the desired angle of said seating structure withrespect to the desired bearing of said structure with respect to thecoordinates of the earth, means for emitting signals responsive to theactual bearing when said support unit or said jib means is moved to adifferent location, comparator means for comparing the departure of saidsignals from the predetermined desired bearing of said seating structureand means responsive to the departure of said signals for actuating saidpivoting means in said two planes for aligning said at least one seatingstructure to a position parallel to the desired bearing, the means forsensing the actual bearing in the horizontal plane including a courseindicator mountd on said at least one seating structure aand responsiveto bearing directions.

12. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like, said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the vertical, means for emitting signals responsive to theangle of said seating structure to the vertical when said support unitor said jib means is moved to a different location, comparator means forcomparing the departure of said signals from the predetermined desiredangle of said seating structure and means responsive to the departure ofsaid signals for actuating said pivoting means in said two planes foraligning said at least one seating structure to a position parallel tothe desired angle, the means for sensing the actual angles in the planesincluding at least one pendulum transducer mounted on said seatingstructure and being active in the two planes disposed at an angle toeach other.

13. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like, said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the vertical and the desired bearing of said structure withrespect to the coordinates of the earth, means for emitting signalsresponsive to the actual bearing and angle of said seating structure tothe vertical when said support unit is moved to a different location,comparator means for comparing the departure of said signals from thepredetermined desired bearing and angle of said seating structure andmeans responsive to the departure of said signals for actuating saidpivoting means in said two planes for aligning said at least one seatingstructure to a position parallel to the desired bearing and angle, themeans for emitting signals responsive to the actual bearing and angle ofsaid seating structure comprising a course and inclination transducermounted for movement with said seating structure for producing threemagnetic field signals, each of which represents three coordinate valuesof a coordinate system which is immovable in relation to the transducer,and corresponding to three earth field components of said coordinatesystem relative to a substantially fixed component of the earth'smagnetic field, and said comparator means compares the actual valuesrepresented by the said magnetic field signals with the values for thedesired bearing and angle and transmits control signals representingdepartures between the actual and the desired values to drive saidpivoting means for obtaining the desired bearing and angle of saidseating structure.

14. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like, said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the vertical and the desired bearing of said structure withrespect to the coordinates of the earth, means for emitting signalsresponsive to the actual bearing and angle of said seating structure tothe vertical when said support unit is moved to a different location,comparator means for comparing the departure of said signals from thepredetermined desired bearing and angle of said seating structure andmeans responsive to the departure of said signals for actuating saidpivoting means in said two planes for aligning said at least one seatingstructure to a position parallel to the desired bearing and angle, themeans for predetermination of the desired angle to the vertical and thedesired bearing including a first selector means for selecting thedesired angle and a second selector means cooperating with said courseindicator for selecting the desired bearing, the means for emittingsignals responsive to the actual bearing and angle of said seatingstructure comprising a course and inclination transducer mounted formovement with said seating structure for producing three magnetic fieldsignals, each of which represents three coordinate values of acoordinate system which is immovable in relation to the transducer, andcorresponding to three earth field components of said coordinate systemrelative to a substantially fixed component of the earths magneticfield, and said comparator means compares the actual values representedby the said magnetic field signals with the values for the desiredbearing and angle and transmits control signals representing departuresbetween the actual and the desired values to drive said pivoting meansfor obtaining the desired bearing and angle of said seating structure.

15. A system according to claim 14 wherein said transducer containsthree field component transducers, each comprising elements which areimmovable with respect to each other and are immovable in relation tothe seating structure and each of which produces component signals whichare set in relation to the said fixed component of the earths magneticfield so that each of said signals constitutes one of said threemagnetic field signals.

16. A system according to claim 15 wherein the desired angle and bearingof said seating structure can be manually adjusted and the systemdetermines, with the assistance of said values, the inclination of theearths field, and the three said magnetic field signals, the two controlsignals each representing one of the values:

Sv sin 'y v sin 'yB cos (11,,

for controlling said pivoting means for the seating structure to obtainthe desired movement in said two planes relative to the vertical, yt and'yv constituting the actual angle of said seating structure, 7,8 beingthe desired angle of the seating structure, and @11 being the anglebetween the desired bearing [3 and the horizontal projection of thecoordinate axis in said coordinate system which extends forward in thedirection of said jib means.

17. A system according to claim 16 wherein the desired values for theangle 75, the bearing ,8, the said substantially fixed component of theearths magnetic field and the inclination of the earths magnetic fieldare capable of being adjusted manually, the two last mentioned valuesbeing capable of being preset, and the inclination being adjustable byadjustment of the vertical component of the earths magnetic field andthe horizontal component to form a ratio of these two components.

18. A rock drilling apparatus comprising a movable support unit, anelongated jib means pivotally mounted on said support unit, a guideseating structure, pivot means between said seating structure and saidjib means providing for movement of said seating structure with respectto said jib means about first and second axes, a feed beam mounted onsaid seating structure, a rock drilling machine mounted for poweredreciprocating movement on said feed beam, hydraulically actuated powerunits operably connected to said jib means and said seating structurefor moving said seating structure with respect to said jib means aboutsaid first and second axes; control means including angle sensing meansmounted on said seating structure for movement therewith and includinggravity responsive means incorporated in said sensing means for movementwith respect to said seating structure in response to gravitationalforces acting on said means, signal producing means for producingsignals in response to the movement of said gravity responsive meanswith respect to said seating structure, and a control circuit includingcontrol valves interposed therein and responsive to the signals fromsaid signal producing means for valving hydraulic fluid to said powerunits'to move said seating structure about said first and second axes tomaintain said feed beam and rock drilling machine in a predeterminedangular direction in relation to the vertical.

the desired angle of said seating structure with respect to thevertical, comparator means for comparing the departure of said signalsfrom the predetermined desired angle of said seating structure. andmeans responsive to said departure of said signals for valving hydraulicfluid to said power units for moving said. seating structure withrespect to said jib means about said first and second axes.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 8 5 88DATED July 29, 1975 INVENTOR(S) Carl Lennart Dahlstrom,et al it iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

claim 1, third line from the end of claim before "pivoting" insert:

- actuating said Claim 11, next to last line spell "mounted thus lastline spell and thus Signed and Sealed this fourteenth Day of October1975 [SEAL] A ttest:

RUTH C. MASON Arresting Officer

1. A system for automatically aligning at least one guide seatingstructure for parallel positions at different locations, said structurebeing adapted for guiding the movement of a tool mounted thereon as afeed beam for rock drilling machines and the like; said systemcomprising a movable support unit, jib means supported on said supportunit, a seating structure pivotally mounted on said jib means, formovement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the vertical and the desired bearing of said structure withrespect to the coordinates of the earth, means for emitting signalsresponsive to the actual bearing and angle of said seating structure tothe vertical when said support unit is moved to a different location,comparator means for comparing the departure of said signals from thepredetermined desired bearing and angle of said seating structure andmeans responsive to the departure of said signals for pivoting means insaid two planes for aligning said at least one seating structure to aposition parallel to the desired bearing and angle.
 2. A systemaccording to claim 1 wherein said comparator means includes transducermeans having means for sensing the actual bearing in the horizontalplane and means for sensing the actual angle in relation to thevertical.
 3. A system according to the claim 2 wherein the means forsensing the actual bearing in the horizontal plane includes a courseindicator mounted on said support unit and responsive to bearingdirections, said course indicator providing a preset desired bearingfrom which all other bearings in the horizontal plane may be determined,and further comprising a second indicator mounted between said supportunit and said jib means, said second indicator resistering the anglebetween said support unit and said jib means.
 4. A system according toclaim 3 wherein the means for predetermination of the desired angle tothe vertical and the desired bearing includes a first selector means forselecting the desired angle and a second selector means cooperating withsaid course indicator for selecting the desired bearing.
 5. A systemaccording to claim 2 wherein the means for sensing the actual bearing inthe horizontal plane includes a course indicator mounted on said atleast one seating structure and responsive to bearing directions.
 6. Asystem according to claim 2 wherein the means for sensing the actualangles in the planes includes at least one pendulum means mounted onsaid seating structure and being active in the two planes disposed at anangle to each other.
 7. A system according to claim 1 wherein the meansfor emitting signals responsive to the actual bearing and angle of saidseating structure comprises a course and inclination transducer mountedfor movement with said seating structure for producing three magneticfield signals, each of which represents three coordinate values of acoordinate system which is immovable in relation to the transducer, andcorresponding to three earth field components of said coordinate systemrelative to a substantially fixed component of the earth''s magneticfield, and said comparator means compares the actual values representedby the said magnetic field signals with the values for the desiredbearing and angle and transmits control signals representing departuresbetween the actual and the desired values to drive said pivoting meansfor obtaining the desired bearing and angle of said seating structure.8. A system according to claim 7 wherein said transducer contains threefield component transducers, each comprising elements which areimmovable with respect to each other and are immovable in relation tothe seating structure and each of which produces component signals whichare set in relation, to the said fixed components of the earth''smagnetic field so that each of said signals constitutes one of saidthree magnetic field signals.
 9. A system according to claim 8 whereinthe desired angle and bearing of said seating structure can be manuallyadjusted and the system determines, with the assistance of said values,the inclination of the earth''s field, and the three said magnetic fieldsignals, the two control signals each representing one of the values: Sttg gamma t - tg Beta .cos psi o Sv sin gamma v - sin gamma Beta .cos psio for controlling said pivoting means for the seating structure toobtain the desired movement in said two planes relative to the vertical,gamma t and gamma v constituting the actual angle of said seatingstructure, gamma Beta being the desired angle of the seating structure,and psi o being the angle between the desired bearing Beta and thehorizontal projection of the coordinate axis in said coordinate systemwhich extends forward in the direction of said jib means.
 10. A systemaccording to claim 9 wherein the desired values for the angle gamma Beta, the bearing Beta , the said substantially fixed component of theearth''s magnetic field and the inclination of the earth''s magneticfield are capable of being adjusted manually, the two last mentionedvalues being capable of being preset, and the inclination beingadjustable by adjustment of the vertIcal component of the earth''smagnetic field and the horizontal component to form a ratio of these twocomponents.
 11. A system for automatically aligning at least one guideseating structure for parallel positions at different locations, saidstructure being adapted for guiding the movement of a tool mountedthereon as a feed beam for rock drilling machines and the like, saidsystem comprising a movable support unit, jib means supported on saidsupport unit, a seating structure pivotally mounted on said jib means,for movement in two planes disposed at an angle to each other, means forpivoting said seating structure in each of said two planes, means forpredetermination of the desired angle of said seating structure withrespect to the desired bearing of said structure with respect to thecoordinates of the earth, means for emitting signals responsive to theactual bearing when said support unit or said jib means is moved to adifferent location, comparator means for comparing the departure of saidsignals from the predetermined desired bearing of said seating structureand means responsive to the departure of said signals for actuating saidpivoting means in said two planes for aligning said at least one seatingstructure to a position parallel to the desired bearing, the means forsensing the actual bearing in the horizontal plane including a courseindicator mountd on said at least one seating structure aand responsiveto bearing directions.
 12. A system for automatically aligning at leastone guide seating structure for parallel positions at differentlocations, said structure being adapted for guiding the movement of atool mounted thereon as a feed beam for rock drilling machines and thelike, said system comprising a movable support unit, jib means supportedon said support unit, a seating structure pivotally mounted on said jibmeans for movement in two planes disposed at an angle to each other,means for pivoting said seating structure in each of said two planes,means for predetermination of the desired angle of said seatingstructure with respect to the vertical, means for emitting signalsresponsive to the angle of said seating structure to the vertical whensaid support unit or said jib means is moved to a different location,comparator means for comparing the departure of said signals from thepredetermined desired angle of said seating structure and meansresponsive to the departure of said signals for actuating said pivotingmeans in said two planes for aligning said at least one seatingstructure to a position parallel to the desired angle, the means forsensing the actual angles in the planes including at least one pendulumtransducer mounted on said seating structure and being active in the twoplanes disposed at an angle to each other.
 13. A system forautomatically aligning at least one guide seating structure for parallelpositions at different locations, said structure being adapted forguiding the movement of a tool mounted thereon as a feed beam for rockdrilling machines and the like, said system comprising a movable supportunit, jib means supported on said support unit, a seating structurepivotally mounted on said jib means for movement in two planes disposedat an angle to each other, means for pivoting said seating structure ineach of said two planes, means for predetermination of the desired angleof said seating structure with respect to the vertical and the desiredbearing of said structure with respect to the coordinates of the earth,means for emitting signals responsive to the actual bearing and angle ofsaid seating structure to the vertical when said support unit is movedto a different location, comparator means for comparing the departure ofsaid signals from the predetermined desired bearing and angle of saidseating structure and means responsive to the departure of said signalsfor actuating said pivoting means in said two planes for aligning saidat least one seating structure to a position parallel to the desiredbearing aNd angle, the means for emitting signals responsive to theactual bearing and angle of said seating structure comprising a courseand inclination transducer mounted for movement with said seatingstructure for producing three magnetic field signals, each of whichrepresents three coordinate values of a coordinate system which isimmovable in relation to the transducer, and corresponding to threeearth field components of said coordinate system relative to asubstantially fixed component of the earth''s magnetic field, and saidcomparator means compares the actual values represented by the saidmagnetic field signals with the values for the desired bearing and angleand transmits control signals representing departures between the actualand the desired values to drive said pivoting means for obtaining thedesired bearing and angle of said seating structure.
 14. A system forautomatically aligning at least one guide seating structure for parallelpositions at different locations, said structure being adapted forguiding the movement of a tool mounted thereon as a feed beam for rockdrilling machines and the like, said system comprising a movable supportunit, jib means supported on said support unit, a seating structurepivotally mounted on said jib means for movement in two planes disposedat an angle to each other, means for pivoting said seating structure ineach of said two planes, means for predetermination of the desired angleof said seating structure with respect to the vertical and the desiredbearing of said structure with respect to the coordinates of the earth,means for emitting signals responsive to the actual bearing and angle ofsaid seating structure to the vertical when said support unit is movedto a different location, comparator means for comparing the departure ofsaid signals from the predetermined desired bearing and angle of saidseating structure and means responsive to the departure of said signalsfor actuating said pivoting means in said two planes for aligning saidat least one seating structure to a position parallel to the desiredbearing and angle, the means for predetermination of the desired angleto the vertical and the desired bearing including a first selector meansfor selecting the desired angle and a second selector means cooperatingwith said course indicator for selecting the desired bearing, the meansfor emitting signals responsive to the actual bearing and angle of saidseating structure comprising a course and inclination transducer mountedfor movement with said seating structure for producing three magneticfield signals, each of which represents three coordinate values of acoordinate system which is immovable in relation to the transducer, andcorresponding to three earth field components of said coordinate systemrelative to a substantially fixed component of the earth''s magneticfield, and said comparator means compares the actual values representedby the said magnetic field signals with the values for the desiredbearing and angle and transmits control signals representing departuresbetween the actual and the desired values to drive said pivoting meansfor obtaining the desired bearing and angle of said seating structure.15. A system according to claim 14 wherein said transducer containsthree field component transducers, each comprising elements which areimmovable with respect to each other and are immovable in relation tothe seating structure and each of which produces component signals whichare set in relation to the said fixed component of the earth''s magneticfield so that each of said signals constitutes one of said threemagnetic field signals.
 16. A system according to claim 15 wherein thedesired angle and bearing of said seating structure can be manuallyadjusted and the system determines, with the assistance of said values,the inclination of the earth''s field, and the three said magnetic fieldsignals, the two control signals each representing one of the values: SttG gamma t - tg Beta .cos psi o Sv sin gamma v - sin gamma Beta .cos psio for controlling said pivoting means for the seating structure toobtain the desired movement in said two planes relative to the vertical,gamma t and gamma v constituting the actual angle of said seatingstructure, gamma Beta being the desired angle of the seating structure,and psi o being the angle between the desired bearing Beta and thehorizontal projection of the coordinate axis in said coordinate systemwhich extends forward in the direction of said jib means.
 17. A systemaccording to claim 16 wherein the desired values for the angle gammaBeta , the bearing Beta , the said substantially fixed component of theearth''s magnetic field and the inclination of the earth''s magneticfield are capable of being adjusted manually, the two last mentionedvalues being capable of being preset, and the inclination beingadjustable by adjustment of the vertical component of the earth''smagnetic field and the horizontal component to form a ratio of these twocomponents.
 18. A rock drilling apparatus comprising a movable supportunit, an elongated jib means pivotally mounted on said support unit, aguide seating structure, pivot means between said seating structure andsaid jib means providing for movement of said seating structure withrespect to said jib means about first and second axes, a feed beammounted on said seating structure, a rock drilling machine mounted forpowered reciprocating movement on said feed beam, hydraulically actuatedpower units operably connected to said jib means and said seatingstructure for moving said seating structure with respect to said jibmeans about said first and second axes; control means including anglesensing means mounted on said seating structure for movement therewithand including gravity responsive means incorporated in said sensingmeans for movement with respect to said seating structure in response togravitational forces acting on said means, signal producing means forproducing signals in response to the movement of said gravity responsivemeans with respect to said seating structure, and a control circuitincluding control valves interposed therein and responsive to thesignals from said signal producing means for valving hydraulic fluid tosaid power units to move said seating structure about said first andsecond axes to maintain said feed beam and rock drilling machine in apredetermined angular direction in relation to the vertical.
 19. A rockdrilling apparatus according to claim 18 and further comprising meansfor maintaining the desired bearing of said seating structure withrespect to said support.
 20. A rock drilling apparatus according toclaim 18 and further comprising means for maintaining the desiredbearing of said seating structure with respect to the coordinates of theearth.
 21. A rock drilling apparatus according to claim 18 and furthercomprising means for predetermination of the desired angle of saidseating structure with respect to the vertical, comparator means forcomparing the departure of said signals from the predetermined desiredangle of said seating structure, and means responsive to said departureof said signals for valving hydraulic fluid to said power units formoving said seating structure with respect to said jib means about saidfirst and second axes.